Perchlorate ions and perchlorate salts, such as, for example, sodium, potassium, and ammonium perchlorates, are known for their excellent oxidizing power. Perchlorates have been used extensively as oxidizers in rocket motor assemblies, pyrotechnics, vehicle secondary restraint systems, flares, military explosives, and other devices employing gas generating or high-energy compositions. Perchlorates are especially suited for use in igniters of such devices, e.g., as part of the ignition train for initiation of combustion of a rocket motor propellant or generation of gaseous products of a gas generant.
Perchlorates are not always completely consumed in use. Rather, the activation of devices such as rockets, pyrotechnics, and explosives often releases perchlorates into the environment as fine dusts, which can be dispersed in the wind. The release of perchlorates from these devices into the environment has sometimes resulted in contamination of surface and ground water supplies. When contacted with water, these compounds dissolve, releasing perchlorate ions. Due to high solubility, perchlorates tend to be very mobile in the environment. For example, perchlorates dissolved in the water may stay in lakes and ponds, or they may be carried long distances by streams and rivers. Perchlorates dissolved in water also may sink into the ground and eventually reach groundwater aquifers. Since perchlorates are characterized by a very high activation temperature, environmental temperatures are generally too low to activate its oxidizing potential. As a consequence, perchlorates can persist unchanged in air, soil, surface water and groundwater for prolonged periods. Further, many species of plants, including those edible to humans and animals, can absorb and accumulate perchlorates from soil.
Studies have linked perchlorates to serious health afflictions. Perchlorate salts and perchlorate ions can potentially enter the human body by inhalation of dust containing the salts, and swallowing of food and drinking water containing the perchlorates. It is believed that human consumption of perchlorates may impair thyroid function in humans, with pregnant women and developing fetuses reportedly being especially vulnerable to injury from perchlorate exposure. It also has been reported perchlorates may increase the likelihood of thyroid cancer.
Due to these health concerns, environmental and other governmental regulations are seeking to phase out perchlorates from use in various industries. Accordingly, it is highly desirable to find a perchlorate replacement that provides comparable or superior oxidizer capabilities to perchlorates, without the potential environmental and health concerns reported to be caused by perchlorates.